California Rapid Assessment Method for Wetlands (CRAM) Riverine Training Module

Transcription

1 California Rapid Assessment Method for Wetlands (CRAM) Riverine Training Module

2 Steps of CRAM Assessment Step 1: Assemble background information Step 2: Classify wetland Step 3: Verify the appropriate season Step 4: Sketch the CRAM Assessment Area (AA) Step 5: Conduct the office assessment of AA Step 6: Conduct the field assessment of AA Step 7: Complete CRAM QA/QC Step 8: Submit assessment results using ecram

3 Assemble Background Information 1-3m pixel resolution digital geo-rectified site imagery with a scale Preliminary map of assessment area (AA) Reports on hydrology, ecology, chemistry List of common plants Access permission (if needed) Map/directions to site

4 Sources of Background Information Wetland Maps (NWI, EcoAtlas) Other maps (topography, geology, soils, vegetation) Project reports (e.g., monitoring reports) Phone interviews

5 Nonconfined Riverine Yes No Valley width is at least twice bankfull width? Riverine Confined Riverine No Hydrology fully or partially tidal for at least 1 month during most years Classify the Wetland Yes Estuarine Yes Flow-through system with channelized flow between distinct inlet and outlet? No Depressional, Seeps, Springs, Lacustrine

6 Nonconfined Riverine Yes No Valley width is at least twice bankfull width? Riverine Confined Riverine No Hydrology fully or partially tidal for at least 1 month during most years Classify the Wetland Yes Estuarine Yes Flow-through system with channelized flow between distinct inlet and outlet? No Depressional, Seeps, Springs, Lacustrine

7 Nonconfined Riverine Yes No Valley width is at least twice bankfull width? Riverine Confined Riverine No Hydrology fully or partially tidal for at least 1 month during most years Classify the Wetland Yes Estuarine Yes Flow-through system with channelized flow between distinct inlet and outlet? No Depressional, Seeps, Springs, Lacustrine

8 Channel Confinement Confined Non-confined

9 Nonconfined Riverine Yes No Valley width is at least twice bankfull width? Riverine Confined Riverine No Hydrology fully or partially tidal for at least 1 month during most years Classify the Wetland Yes Estuarine Yes Flow-through system with channelized flow between distinct inlet and outlet? No Depressional, Seeps, Springs, Lacustrine

10 CRAM Assessment Window Growing season of plants Usually March September o New growth to senescence o Shorter at higher altitudes o Later with snow o Riverine not during high water

11 Considerations for defining the AA Purpose of Assessment Project (multiple AAs to cover site) Ambient (AA located at probabilistic draw point) Hydrogeomorphic Integrity Bounded by changes in flow and sediment regimes Maximize detection of management effects Size Limits for AAs Larger AAs have higher or more variable scores Larger AAs take longer to assess

12 Sketch the AA AA is the channel, its active floodplain, and essential riparian area Length = 10x mean BF width within limits of 100m and 200m 100m

13 AA includes portion of riparian area directly affecting channel Lateral extent of AA including riparian area that contributes allocthanous material to the channel and its immediate floodplain Back Edge of Floodplain Bankfull Channel at low flow AA lateral width includes portion of riparian area that directly provides allochthonous input to the channel and immediate floodplain (2m min. width)

14 Special Considerations for Certain Systems Large systems with very broad floodplains (10-20 X average channel width) Examples of large systems include: o Santa Ana River, San Joaquin River, Sacramento River, etc Narrow systems in a steep valley lacking a floodplain In these systems, make lateral extent of AA no more than 2 times bankfull width on each side of the channel.

15 Special Considerations for Certain Systems Large systems with very broad floodplains (10-20 X average channel width)

16 Ground view of large system. Examples include: Santa Ana and Santa Margarita Rivers in southern California Sacramento River and Eel River in northern California

17 Field Assessment Procedure 1. Bring printed aerial photographs 2. Walk the wetland and draw the AA 3. Walk through entire AA making mental notes and recording important plant species 4. Fill out datasheets 5. Walk again to clarify uncertainties 6. Finalize field scores

18 Basic Information Datasheet

19 Buffer and Landscape Context Attribute Upstream and downstream continuity of stream corridor Size and quality of buffer surrounding AA

20 Stream Corridor Continuity (Aquatic Area Abundance Metric) Assume riparian area average width is the same upstream and downstream of the AA as it is within the AA To be a concern, a segment of non-buffer cover must: extend across at least one side of the riparian area extend at least 10 m along the channel break on both sides (ex. from a bridge) gets counted twice, once for each side For systems that cannot be waded, assess the riparian corridor on the side of the river being assessed For wadeable systems assess the riparian continuity on both sides of the stream

21 Stream Corridor Continuity Assess the total length of non-buffer segments 500m upstream and 500m downstream of the AA Urban parkland breaks downstream connectivity on one side Narrow bridge slightly breaks downstream connectivity on both sides AA 500m upstream and downstream

22 Rating for Stream Corridor Continuity Rating Aggregate length of non-buffer segments upstream 500m of AA A Less than 100m Less than 100m Aggregate length of non-buffer segments downstream 500m of AA B Less than 100m Between 100m and 200m B Between 100m and 200m Less than 100m C Between 100m and 200m Between 100m and 200m D Greater than 200m Any condition D Any condition Greater than 200m (2 sided) or or

23 Percent of AA with Buffer Estimate percent of the AA perimeter adjoining non-buffer land cover that is at least 5m wide and 5m long. ~40% of AA perimeter has buffer Non-buffer cover

24 Guidelines for Identifying Buffers and Breaks in Buffers

25 Rating for Percent of AA with Buffer Rating A B C D Alternative State Buffer is % of AA perimeter Buffer is 50 74% of AA perimeter Buffer is 25 49% of AA perimeter Buffer is < 25% of AA perimeter

26 Average Buffer Width A B C D E F G H 100m Line A = 45m Line B = 35m Line C = 30m Line D = 25m Line E = 20m Line F = 15m Line G = 10m Line H = 5m Avg. 185/8 = 23m

27 Rating for Average Buffer Width Rating A B Alternative State Average buffer width is m. Average buffer width m. C Average buffer width is m. D Average buffer width is 0 64 m.

28 Buffer Condition Buffer characteristics examined: Native vs non-native vegetation Soil disturbance or compaction Intensity of human visitation Assess Based on Field Indicators Only

29 Rating for Buffer Condition Rating A B B C D Alternative States Buffer for AA is dominated by native vegetation, has undisturbed soils, and is apparently subject to little or no human visitation. Buffer for AA is characterized by an intermediate mix of non-native and native vegetation (25% to 75% non-native), but mostly undisturbed soils, and is apparently subject to little or low impact human visitation OR Buffer for AA is dominated by native vegetation, but shows some soil disturbance, and is apparently subject to little or low impact human visitation. Buffer for AA is characterized by substantial amounts (>75%) of non-native vegetation, AND there is at least a moderate degree of soil disturbance/compaction, and/or there is evidence of at least moderate intensity of human visitation. Buffer for AA is characterized by barren ground and/or highly compacted or otherwise disturbed soils, and/or there is evidence of very intense human visitation.

30 Buffer Condition A C

31 Hydrology Attribute Primary source of water Stability of channel Restriction of lateral movement of floodwaters

32 Consider fresh water source(s) Determine anthropogenic inputs, diversions, or modified hydrology within the upstream immediate drainage basin Consult information sources Watershed reports Local experts Maps or imagery Water Source 2 km

33 Water Source Stream diversion by the City of Watsonville causes the creek to run dry in summer (late July) just below the town of Corralitos. Small tributaries, or field runoff, add water to the creek bed downstream of this point Coastal Watershed Council CORRALITOS CREEK WATERSHED FINAL ANNUAL REPORT JULY-DECEMBER 2003

34 Rating for Water Source

35 Channel Stability Consider indicators of channel stability, aggradation, and degradation (incision) Aggradation Degradation

36 Channel Stability Field Indicators: Equilibrium Leaf litter in pools Well-sorted bed material Abundant mosses Abundant perennial vegetation above bankfull contour Well defined bankfull contour Non-planar bed

37 Channel Stability Field Indicators: Aggradation Partially buried culvert/bridge Planar bed lacking pools Buried living tree trunks

38 Channel Stability Field Indicators: Degradation Exposed roots Deeply undercut banks Vegetation falling into channel

39 Rating for Channel Stability Rating A B C D Alternative State Most of the channel through the AA is characterized by equilibrium conditions, with little evidence of aggradation or degradation. Based on the indicators of condition, typical sediment transport processes are occurring. Most of the channel through the AA is characterized by some aggradation or degradation, none of which is severe. The channel may be approaching or moving away from equilibrium. Based on the indicators of condition, typical sediment transport processes are occurring, however the reach is trending toward excess transport or deposition due to moderate disequilibrium conditions. There is evidence of severe aggradation or degradation of most of the channel through the AA or the channel bed is artificially hardened through less than half of the AA. Based on the indicators of condition, typical sediment transport processes are severely altered. The channel bed is concrete or otherwise artificially hardened through most of AA.

40 Hydrologic Connectivity Degree of entrenchment is used to assess lateral connections between the channel and its floodplain Step 1: Estimate bankfull width (bfw) Step 2: Estimate maximum bankfull depth Step 3: Estimate flood prone depth Step 4: Estimate flood prone width (fpw) Step 5: Calculate entrenchment ratio (fpw/bfw) Step 6: Average of three ratio measurements

41 Riverine Confinement and Entrenchment A. Non-confined Entrenched B. Non-confined Not Entrenched Valley Width A B Bankfull Width C D C. Confined Not Entrenched D. Confined Entrenched

42 Identifying Bankfull Width Suite of field indicators for Bankfull Inner Edge of floodplain Top elevation of point bars Lower limit of bank vegetation Lower limit of riparian litter

43 Identifying Bankfull Width Bankfull can be difficult to discern Most difficult in unstable reaches Best on straight reaches of uniform slope Multiple observers Multiple points of measurement See the tips page on CRAM website Video - A Guide for Field Identification of Bankfull Stage in the Western United States US Forest Service

44 Measuring Entrenchment to Score Hydrologic Connectivity Flood Prone Width Bankfull Width Flood Prone Depth Bankfull Depth

45 Step 3: Flood Prone Height 2.58 m Step 4: Flood Prone Width m Step 2: Bankfull Height 1.29 m Step 1: Bankfull Width 6.55 m

46 Hydrologic Connectivity Step 1: Estimate bankfull width (bfw) Step 2: Estimate maximum bankfull depth Step 3: Estimate flood prone depth Step 4: Estimate flood prone width (fpw) Step 5: Calculate entrenchment ratio (fpw/bfw) Step 6: Average of three ratio measurements 1.59

47 Rating of Hydrologic Connectivity for Non-Confined Riverine Rating A B C D Alternative State based on the entrenchment ratio calculation Entrenchment ratio is > 2.2 Entrenchment ratio is 1.9 to 2.2 Entrenchment ratio is 1.5 to 1.8 Entrenchment ratio is <1.5

48 Rating of Hydrologic Connectivity for Confined Riverine Rating Alternative State based on the entrenchment ratio calculation A Entrenchment ratio is > 1.8. B Entrenchment ratio is 1.6 to 1.8. C Entrenchment ratio is 1.2 to 1.5. D Entrenchment ratio is < 1.2.

49 Richness of structural surfaces reflects diversity of physical processes: o o o o Energy dissipation Water storage Groundwater exchange Flood attenuation Physical complexity promotes ecological complexity and increases: o o o Physical Structure Attribute Ecological functions Beneficial uses Overall condition

50 Physical Structure Attribute Composed of two metrics: Structural patch richness o Number of patch types within AA o Different for confined and non-confined Topographic complexity o Variety of elevations (benches) and extent of microtopography within AA

51 Structural Patch Richness Large woody debris Boulder in channel Riffle In-channel bar Pool in channel

52 Structural Patch Richness Patch Type Table Debris Jam Hummocks

53 Rating for Structural Patch Richness (non-confined riverine shown here) Rating Alternative States A 12 of the possible patches types present B 9-10 of the possible patches types present C 6-7 of the possible patches types present D 5 of the possible patches types present Variegated Shore Non-Variegated Shore

54 Topographic Complexity Assess from lateral edge of AA to lateral edge of AA Macrotopography Microtopography

55 Rating of Topographic Complexity Rating A Alternative States (based on worksheet and diagrams in Figure 10 above) AA as viewed along a typical cross-section has at least two benches at different elevations (not including the channel bottom or high riparian terraces not influenced by fluvial processes). Features below the bankfull elevation are part of the active channel and cannot be considered benches. Additionally, each of these benches, plus the slopes between the benches, contain physical patch types or micro-topographic features such as boulders or cobbles, partially buried woody debris, undercut banks, secondary channels and debris jams that contribute to abundant micro-topographic relief as illustrated in profile A. AA has at least two benches above bankfull elevation, but these benches mostly lack abundant micro-topographic complexity. The AA resembles profile B1. B OR AA has one bench above bankfull elevation, and this bench has abundant microtopographic complexity as described in the A condition above. The AA resembles profile B2. C D AA has a single bench that lacks abundant micro-topographic complexity, as illustrated in profile C. AA as viewed along a typical cross-section lacks any obvious bench. The cross-section is best characterized as a single, uniform slope with or without micro-topographic complexity, as illustrated in profile D (includes concrete channels).

56 Macro-topographic Indicators 2 1 Two Benches 1 One Bench

57 Micro-topographic Indicators Pools, pits, bars, debris jams Cobble, bank slumps, tree fall holes

58 Biotic Structure Attribute Considers Overall ecological complexity of plant community of the wetland Three metrics: Plant Community Composition Horizontal Interspersion and Zonation Vertical Biotic Structure

59 Plant Community Metric Submetrics Number of Plant Layers Present o A layer must cover at least 5% of the portion of the AA that is suitable for the layer Number of Co-dominant Species o For each plant layer, every species represented by living vegetation that comprises at least 10% relative cover within the layer is considered to be dominant in that layer. Percent Invasion o o The number of invasive co-dominant species for all plant layers combined is assessed as a percentage of the total number of codominants. The invasive status for California wetland and riparian plant species is based on the Cal-IPC list.

60 Determining Plant Community Submetrics Step 1 : Determine number of plant layers Not counted as a layer NO 5% absolute cover YES Counted as a layer Step 2 : Determine co-dominant plant species per layer Not counted as a dominant NO 10% relative cover YES Counted as a dominant Step 3 : Sum unique co-dominants and determine % that are invasive

61 Defining Plant Layers

62 Rules for Plant Community Metric Plant Layers: identified by actual plant heights, regardless of the growth potential of the species Co-dominant Species: can exist in multiple layers, a given plant species is counted only once when calculating total number of co-dominants and percent invasive spp. Dead vegetation can count as a layer, but is not included in the dominant species count Vines are counted in the layer of vegetation they are covering

63 Plant Community Metric Worksheet

64 Ratings for submetrics of Plant Community Metric

65 Horizontal Interspersion Interspersion: the number of distinct plant zones and the amount of edge between them Scoring is based upon field observation and aerial image interpretation Plant zones: plant monocultures or multi-species associations Remain relatively constant in makeup throughout the AA Arrayed along gradients of elevation, moisture, etc., that affect the plant community organization in 2-D plan view

66 Rating for Horizontal Interspersion Based on Worksheet drawing and Figure 10 of field book Rating A Alternative States AA has a high degree of plan-view interspersion. B AA has a moderate degree of plan-view interspersion. C D AA has a low degree of plan-view interspersion. AA has minimal plan-view interspersion.

67 Horizontal Interspersion High Minimal

68 Horizontal Interspersion High Minimal

69 Vertical Biotic Structure Assesses the degree of overlap among plant layers. The same plant layers used to assess the Plant Community Composition Metrics are used to assess Vertical Biotic Structure.

70 Vertical Biotic Structure

71 Vertical Biotic Structure Abundant Overlap requires 3 or more layers

72 Vertical Biotic Structure Moderate Overlap requires 2 layers

73 Rating for Vertical Biotic Structure Rating A B C D Alternative States More than 50% of the vegetated area of the AA supports abundant overlap of 3 plant layers. More than 50% of the vegetated area of the AA supports at least moderate overlap of 2 plant layers. 25%-50% of the vegetated area of the AA supports at least moderate overlap of 2 plant layers Less than 25% of the vegetated area of the AA supports moderate overlap of 2 plant layers OR AA is sparsely vegetated overall.

74 Review map of AA CRAM Initial QA/QC Review CRAM results Complete all CRAM data fields Add comments as needed Complete stressor checklist Ensure photographs, GPS points and any plant voucher specimens have been collected

75 Scoring Sheet: Riverine Wetlands Buffer and Landscape Context Attribute Hydrology Attribute Physical Structure Attribute Biotic Structure Attribute Overall AA Score

76 Wetland Disturbances

77 Stressor Checklist Important to record nature and degree of stressors Contributes to interpretation of CRAM score and future trends or predictions for AA May contribute to future module evaluation and development

78 Upload CRAM Results Enter data using ecram online Benefits of Statewide database: Increasingly required for regulatory applications Contributes to statewide dataset Enables comparisons to other cases

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